How smokers metabolise nicotine could help choose best quitting method

In collaboration with the Press Association

Measuring the rate at which smokers break down (metabolise) nicotine could help predict how well certain quitting methods would work for them, according to a preliminary study published in The Lancet Respiratory Medicine.

"We're a long way from knowing whether, in practice, it would be helpful or cost-effective to offer different medications to different people trying to quit." - Nicola Smith, Cancer Research UK

If confirmed in further studies, it could lead to better tailoring of smoking cessation advice, such as the NHS Stop Smoking Services.

The researchers used a measure known as the nicotine metabolite ratio (NMR) to estimate how quickly nicotine was cleared from the systems of 1246 smokers. NMR takes into account both the environmental and genetic effects on nicotine metabolism, and can be used to divide people into ‘normal’ or ‘slow’ metabolisers.

According to some estimates, around two thirds of people are thought to be ‘normal’ metabolisers. Previous research has shown that they are more likely to smoke more, and can find it more difficult to quit as nicotine levels drop more quickly in their bodies.

The researchers, led by Professor Caryn Lerman at the University of Pennsylvania, found that people who break down nicotine at normal rates were twice as likely to quit when they used the non-nicotine replacement therapy drug varenicline (Chantix or Champix) as opposed to nicotine patches.

Normal metabolisers taking varenicline were also more likely to still be smoke-free after six months.

In contrast, there was no significant difference in success rates for different treatments in people with a slower nicotine metabolism.

Professor Lerman suggested that matching treatments based on the rate at which smokers metabolise nicotine could be a viable way to help choose a method that is most likely to be successful.

However, Nicola Smith, senior health information officer at Cancer Research UK, cautioned that there was a way to go before the research could be put into practice.

“Although this avenue will be interesting to explore further, we’re a long way from knowing whether, in practice, it would be helpful or cost-effective to offer different medications to different people trying to quit in the UK,” she said.

“There are many other factors that could affect a person's choice of aids to help them give up smoking. The Stop Smoking Services can advise on the options and their specialist support greatly improves the chances of quitting successfully rather than going it alone”.

This study was part of the largest ever study looking at how genetic differences affect tobacco dependence and quitting. 


  • Lerman, C. et al. (2015). Use of the nicotine metabolite ratio as a genetically informed biomarker of response to nicotine patch or varenicline for smoking cessation: a randomised, double-blind placebo-controlled trial, The Lancet Respiratory Medicine, 3 DOI: 10.1016/S2213-2600(14)70294-2